Thanks +Arjun Comar
, "--pgml g++" is exactly what I was looking for! It does not help in my case, because (1) I need networking and getaddrinfo() does not work with statically linked programs (on different systems), and (2) static libicuuc complains about unresolved reference icudt52_dat.
But I managed to get rid of the dependency on icu: this dependency came from http-conduit / http-client via indirect dependency on publicsuffixlist (seriously?!). This latter is built with 'create' flag in the system package. When I rebuilt it locally without 'create', it no longer wanted icu libraries.
So in the end my program, dynamically linked but without dependency on icu, becomes "portable enough" as an executable.